Magneto



J. F. MARTIN Nov. 8, 1932.

MAGNETO Filed Aug. 16 1930 3 Sheets-Sheet 1 4 v IWI ATTORNEY Nov. s, 1932. J F, MAW@ 1,887,320

MAGNET() Filed Aug. 16 1930 3 Sheets-Sheet 2 ATTORNEY v Nov. 8, 1932.

J. F. MARTIN MAGNETO Filed Aug. 16, 1930 3 Sheets-Sheet 3 INVENTQR J//w F/ff ATTORNEY liso Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE JOHN F. MARTIN, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO AMERICAN BOSCH MAGNETO CORPORATION, OF SPRINGFIELD, MASSACHUSETTS, A CORPORATION F NEW YORK MAGNET() Application led August 16, 1930. Serial No. 475.709.

The invention relates to improvements in igniters, and particularly to a magneto to generate electric current for internal combustion engines.

An object of the invention is to provide a magneto of the inductor type, which is comparatively small in size, compact in form and in arrangement of its parts, light in weight and so constructed that the members thereof can be quickly fitted together.

A further object is to provide a magneto in which the bearings for the rotor can be easily and accurately alined when the stationary parts of the device are assembled; and

the. rotor thus given its true concentric position relative to the pole pieces of the permanent magnets, with a minimum air gap or clearance space between said pole pieces and the polar faces on the rotor cooperating therewith.

Another object is to provide a magneto with a housing or framework that is very simple in design and of restricted dimensions, permitting access very readily to the members carried by it; and enabling the axial length of the housing, andparticularly the distance between the main bearings for the shaft of the rotor, to be materially decreased.

Additional objects and advantages of the invention will be made clear Lin the following description, taken with the accompanying drawings upon which one or more of the embodiments of the invention are illustrated. The disclosure, however, is explanatory only and changes in details may of course be made without departing from the principle of the invention or exceeding the scope of the terms of the appended claims.

On the drawings,

Fig. 1 shows a vertical longitudinal section through a magneto according to my invention; Fig. 2 is a transverse vertical section on theline 2 2 of Fig. 1; Fig. 3 is an end view of the stator of this type of magneto; Fig. 4 is a side view thereof seen from the right of Fig. 3; Fig. 5 is a top plan thereof; Fig. 6 is a section on the line 6-6 of Fig. 4; Fig. 7 is a detail showing the shape of the rotor of the magneto; Fig. 8 is a view of another detail indicating how the cover is held upon the magneto; Fig. 9 is a longitudinal vertical section of a similar magneto for a multicylinder engine; and Fig. 10 is a top plan of the front part of the magneto shown in Fig. 9.

The same numerals identify the'same parts throughout.

The magneto shown in Figs. l to 8 inclusive comprises a framework or housing 1, which can be cast or otherwise produced in a single piece. Thisl framework may have the gen# eral form of a fiat plate provided with a peripheral rim 2. Within the framework or housing 1 are the windings 3, the permanent magnet 4 and the rotor 5. The windings 3 are of course stationary and so are the polepieces at the ends of the magnet 4 through which the magnetic flux is passed to energize the windings 3. Ordinarily the magneto will be so mounted that the housing 1 will occupy an upright position with the windings 3 above the rotor 5. Below this rotor is a wide pole piece 6 secured to the adjacent end of the magnet 4; and the windings 3 have a magnetic core 7 to be magnetically connected to the opposite end of the magnet so that when the rotor is in proper position between the core 7 and pole piece 6 the entire flux of the magnet will permeate the windings 3. Parallel with the core 7 is another magnetic path indicated at 8 in Fig. 4, so that when the rotor passes out of line with the end of core 7 and comes into position to bridge the space between the end of path 8 and pole piece 6, all ofthe flux of the magnet 4 will be'bypassed around the windings 3. Both the core 7 and the path 8 together with the pole piece 6 and the rotor 5 are made of laminated mag: netic material, as will be fully set forth herein later.

The rotor 5 is revolved by a shaft or spindle 9 on which it is rigidly mounted. This shaft is supported adjacent one end in the housing 1 and at its other end by an end plate 11 which is securely fastened in place. The inside of the framework 1 is made of increased thickness about the shaft 9, and this thick portion is hollowed out to provide a cavity or pocket 12 for an anti-friction bearing to engage the shaft 9. This bearing may be either a ball-bearing or a roller-bearing, the anti-friction elements of which are indicated at 13 disposed in a holder 14, which is snugly received in recess 12.. This bearing need not be further described, as various` types of bearing can easily be obtained to serve this purpose. The adjacent extremity of shaft 9 projects through a suitable washer 15 which is received in a recess at the bottom of cavity 12, and through the opening 16 to the outside of the housing of the magneto so that the rotor can easily be coupled to a source of power to drive it. The rear end plate 11 is also provided with an inside cavity 12 for a similar anti-friction bearing and the inner end of shaft 9 projects through an opening 17 in the plate 11 into the space between this plate and the magnet 4.

This means for mounting the shaft 9 so as to aline the bearings for the shaft and to dispose and maintain the rear end plate 11 in correct position constitutes an important feature of this invention. It will be seen that the laminations making up the core 7, the magnetic path 8 and the pole piece 6 are held fast between two bearing rings 18 and 19, one of which is securely attached to the inside of the housing 1 in such manner that these rings and the shaft 9 are concentrically supported. The entire poleshoe assembly'or unit consisting of the core 7, path 8 and piece 6 is bound together bi' means of screws passin entirely through t e laminated structure rom one Side to the other. When this unit is mounted `in the proper position as by screwing it with one side against the inside of the framework 1, the rear end plate 11 can be supported by fastening it to the other side of the pole shoe assembly, as shown clearly in Fig. 1. The two bearings for the shaft 9 will thus hold the shaftso asto mount the rotor centrally inthe space between the pole pieces 6 and the ends of the core 7 and path 8 so that the rotor can be revolved freely with only a small distance between its opposite convex polar faces and the concave faces of the pole pieces 6 and of the ends of the parts 7 and 8 above mentioned. j Y

The iner edges of the'rings 18 and 19 are of course substantially circular and of about the same diameter asthe circle which defines the common arc,` off-curvature of the inner face of the pole piece. 6 and the polar faces or lower ends'of path 8 and core v7. (See Fig. 4.) At the upper and lower ends of the windings 3 are insulating washers 20, and the core is made of the laminations 21. These laminations 21 are somewhat wider between the upper ends of the rings 18 and 19 than within the windings 3 to give the desired extent of pole piece to cooperate with the rotor; and these laminations extend up to the top of the windings 3, and terminate flush therewith. The laminations 21 lie between end laminations 22 which are of the same shape as laminations 21, but are longer and project beyond the top of windings 3 so as to receive between them the inside laminations 23 of the magnetic path 8. The laminations 23 have substantially the shape of an inverted L with the base of the L on top of the windings 3 and the shank of the L running downward along the outside of windings 3 and terminating between the rings 18 and 19, between the lower end of the core 7, and the end of the pole piece 6. The outside laminations for the pathv8 are indicated at 24, and their upper horizontal portions are'somewhat shorter than the horizontal portions of the inside laminations 23. The horizontal portions'of the laminations 24 thus terminate at one side of the outside laminations 22 while the ends of the horizontal parts of the laminations 23 lie between the upper ends of the outside laminations 22 of the core 7. The adjacent extremity of the magnet 4 makes contact with all of the laminations of the core 7 and path 8 while the other end of the magnet makes contact with the pole piece 6. In Fig. 1 the laminations 21 and 22 are broken away below the windings 3 to show the laminations 23 and 24 behind them.

The rings 18 and 19 are of some non-magnetic material and rivets 25 also of nonmagnetic material pass through the rings and laminations to hold the rings and laminations together. The pole piece 6 is magnetic and is extended at one end towards the end of the core 7. The inside or polar face of the pole piece 6 and of the ends of the core 7 and magnetic by-pass 8, and of the opposite curved ends of the rotor 5, which has the shape shown in Fig. 7, are of such extent that while one end of the rotor is revolving past the end of the core 7, the other end of t e rotor does not travel beyond the pole piece 6 when the rotor leaves the end of the core 7 and comes into proximity with the end of the path 8. When this'occurs the magnetic flux is withdrawn from windings 3 and shunted around the windings. Hence the magnetic flux can be passed through the windings 3 and withdrawn therefrom to' be by-passed around the windings twice in each revolution.

The supporting ring 18 and end plate .11, as indicated particularly in Fig. 2, are out away along the lowerV edges so that the adjacent end of the magnet 4 can pass under the ring and plate, across the width of the pole piece 6 to the supporting ring 19. The hollow thickened portion of the housing 1 surrounding one bearing for the shaft 9 has. an annular shoulder 26 against which the ring 19 is disposed. The inside face of the plate 11 has a similar shoulder 26a to en gage the other ring 18. Screws 28 attach the end plate 11 to the ring 18, entering holes 29 therein; and `similar screws 30 afiix the ring 19 to the framework 1. The pole shoe assembly is thus firmly mounted on the interior of the housing and the rear end plate 11 is secured to the plate 18. This construction, as has already been 'pointed out, determines the correct position for the shaft 9, the anti-friction bearings, and the rear end plate 11, so that the parts can be easily and accurately iitted together and the rotor mounted to revolve freely with a minimum of clearance bet-Ween its ends and the laminations making up the parts 6, 7 and 8. The shoulders 26 and 26a against which the rings 18 and 19 abut, provide annular ribs or projections 27 and 27a respectively upon the inside faces of the housing 1 and plate 11, one of which supports the ring 18 and the other of which centers the plate 11, as clearly indicated in Fig. 1.

The type of magneto indicated in Figs. 1 to 8 inclusive, has connections for a single cylinder only; and the windings 3 may comprise a low tension and high tension coil, the latter having a terminal 3l for the lead 32 -to be connected to the sparkplug of the engine; this lead passing out of the housing 1 through the insulating bushing 33. Aiiixed to one of the laminations 24 may be a clip 34 for a condenser 35. This clip may be perforated at its ends to receive a fastening screw 36 and binding nut to attach thereto the grounded end 37 of the low tension coil; the other end of the low tension coil 38 running to one terminal of the condenser, whose opposite terminal is joined to a lead 39 running to ground. The lead 38 is continued through a lead 40vto the interrupter. interrupter is made up of parts carried on the outside of plate 11. At 41 is a piece of insulation on which is mounted the breaker lever 42. This lever cooperates in the usual way with a stationary contact on a screw 43 mounted in a projection 44 on the plate 11. A spring 45 is attached to the insulation 41 and lever 42 'to hold the lever against the element 43. Lever 42 is metal and connects to the lead 40, and the element 43 is of course grounded. When the rotor is in the right position, a cam 46 on the end of the shaft 9, projecting outside of the plate 11, will permit the breaker 42 and element 43 to engage'each other momentarily and then separate these two parts. The clip 34 can be connected to ground so that the circuit is made and broken between the lead 37, lead 38 and lead 49, breaker lever 42 and element 43 to ground. Condenser 35 as usual will be connected across the element 43 and lever 42. Suitable pins or the like 47 hold the insulation 41 in place on plate l1.

Inside the housing l are projections 48 between which lie the ends of the magnet 4. One end of this magnet abuts the ring 19 and the other end abuts a projection 49 adjacent to The breaker or .Y

bushing 33. The upper end of the magnet 4 is engaged at one side by a. screw 50 mounted in a threaded opening in rim 2 so as to hold the magnet fast.

As shown in Fig. 1, the magnet 4 and shaft 9 project beyond the edge of the rim 2. To house the magnet, the windings, the pole shoe assembly, rotor and bearings completely, the rim 2 is provided with a groove 52 to receive the edge of a cover 53. At the sides of the housing 1 are projections 54 adjacent the edge of the rim 2 and the cover 53 has a fastening clip or band 55, the middle of which is secured to the center of the cover, and the ends of the yfastening clip are bent as shown at 56 so that when the cover is put on, the ends of the fastening clip can be slipped past behind the projections 54 and take hold of these projections to keep the cover from coming oil". It is only necessary to disengage the ends 56 from the projections 54 to remove the cover and give access to the inside of the magneto as desired. On the magneto is a binding post 57 for grounding purposes.

Figs. 9 and 10 show a magneto for a 4- cylinder engine. Here the housing la is open in front and to the rear edge of the housing is attached a cover 53a. The magnet, the windings 3, the pole shoe assembly and the rotor are within the cover; and the end of the housing 1a to which the cover is fitted will have a transverse partition 58 across the lower half thereof. This partition will have an opening 59 for the shaft 9 and the outer face of the partition 58 will have a shoulder 26 surrounding a circular rib 27 to support and carry the ring 19. The cover 53a may be made fast to the housing 1a in any suitable manner, and the pole shoe assembly will be built up and the end plate 11 fitted to the ring 18 the same as in the previous construction. Also the timer and its parts and connections will be the same as above described. The other end of the housing 1a is open, but at the lower part, detachably secured thereto, is a front plate 61 the inside of which is provided with a recess 12 for the front anti-friction bearing of the shaft 9. This bearing will be the same as the bearing carried by the framework 1. The upper half of the front of the housing 1a will have an opening 62 which will be closed by a distributor plate 63 of insulation, a gasket ring 64 being placed between the plate 63 and housing la, and the plate 63 having a ribwhich projects into the parts 64. Suitable fastening devices may be employed to hold the plate 63 in engagement with the part 64 which is screwed to the housing la.

The shaft in this form of magneto is thus longer than the shaft in the first form to enable the distributor rotor t0 be mounted between the distributor plate 63 and the windings 3, but the bearings can be alined and the rotor 5 mounted in central position as easily as before. The rotor is held fast on the shaft 9 between collars 65 and 66 in both the modifications herein described.

The inside of the plate 63 is dished and carries a ring of insulation 67 bearing inset metallic contact pieces 68 spaced suitable distances apart. These contact pieces are held in place by screws 69 which project into bores leading into sockets 7() to receive the high tension leads of the magneto. Vhen these screws 69 are turned up, the leads are engaged and held fast. The web which extends from the top of the partition 58, first towards the distributor plate 63 and then to the top of the housing la between the Windings 3 and opening 62, has a central bearing 71 to receive the rotatable brush carrier or rotor 72 of the distributor, this carrier being also of insulation. At the front end of this carrier is a laterally extending arm 7 3, and encircling the carrier 72 behind the arm 73 is a gear 74, meshing with a gear 75 of one half the diameter of gear 74 on the shaft 9 between the plate 61 and partition 58. Within the carrier 72 is a metal stem 76 one end of which is hollow to receive one terminal 31a of the high tension coil of the windings 3. In the bore; of the pin 76 is a spring 77 engaging the bottom of the bore and the terminal 31a. The opposite end of the pin 76 is secured to a metal strip 78 extending along the arm 73 and at the outer end of this arm is a protuberance 79, which passes through an opening in the gear 74. This protuberance is hollow and carries a brush to make c ontact in succession with the pieces 68. Inside the protuberance 79 may be a metal lining receivin the brush 80 and containing a spring similar to the spring 77 to insure contact between the brush 80 and pieces 68.

The upper part of the web 60 has an oil insulating duct 8l containing a piece of wick 82 and closed at its outer end by a screw plug 83. The wick extends through a jacket in the bearing 71 and rubs against a similar jacket 84 within the jacket 85. This wick may be omitted if desired. Both jackets 84 and 85 are flanged over adjacent to gear 74. vThe flange of jacket 85 abuts the flange of jacket 84 and the extremity of this jacket 84 beyond the flange thereon passes through the gear and terminates in a recess 86 in the opposite face of the gear 74. Within the ring is a metallic washer 87 and the extremity of the bushing 84 is expanded to bind against this washer and make the bushing 84 rigid with the gear to act as a hub therefor.

The housing la may also be provided with an insulating binding post 88 connected with the lead 89 and serves for grounding purposes. On the end of the shaft 9 projecting through the plate 61 is a gear 90 to enable the magneto to be driven from one of the moving parts of the engine.

described my invention what I framework, an end plate supported by said stator members, bearings in said framework and said end plate, a shaft in said bearings, a rotor on said shaft, a magnet to provide a magnetic flux for the stator members, the plane of the magnet being at right angles to that of the stator members, and a cover attached to the housing and enclosing the rotor and stator members.

2. A magneto comprising a pair of supporting rings, a coil having a magnetic core terminating in a pole piece between said rmgs, means for providing a magnetic path outside of said core and terminating in another pole piece between said rings, a third pole piece between said rings, a magnet to pass a iiux through said core and around the same, a framework to engage and support one of said rings, and an end plate shaped to engage and be directly supported solely by the other of said rings.

3. A magneto comprising a framework, a

pair of supporting rings, pole pieces between said rings, means for binding said rings and said pole pieces together, the framework having a portion shaped to engage and support one of said rings, an end plate shaped to engage and be directly supported solely by the other of said rings, said portion and said plate having cavities for carrying antifriction bearings in exact alinement, a shaft engaging said bearings and a rotor on the shaft mounted in central position by the bearings.

4. In a magneto, a stator structure comprising a coil having a core, one end ofthe core terminating in a pole shoe, means providing a magnetic by-pass at one 'side of the coil, said means also terminating in a pole shoe, and supporting rings atached to each side of said pole shoes.

5. A magneto according to the preceding claim wherein a third pole piece is mounted between said rings and rigidly secured thereto.

6. In a magneto, a stator comprising generating windings, a core consisting of laminations in said windings, a second core comprising L-shaped laminations connected to` one end of the first core and passing along the side of said windings, the opposite ends of said cores being spaced apart, supporting rings attached to said cores with said ends of the cores between them, a pole piece of relatively great width between said rings and a magnet to engage said cores and the last named pole piece and spaced to pass a magnetic flux through said windings' and around the same.

7. A magneto comprising a housing, a roplate with an upturned `rim, stator members mounted within said tor in the housing, a stator in the housing, the housing being closed at one end and open at the other, said open end having a groove therein, a cover having its edge received in said groove, and means for holding the cover and housing together. p

8. A magneto comprising a housing with a partition at one end, said partition having a central opening, a shaft passing through said opening, a rotor on said shaft, a pole shoe assembly supported by said partition around said opening, an end plate secured directly to said assembly and supported solely thereby, a bearing in said end plate, a shaft for the rotor engaging said bearing, and a bearing for the shaft at the opposite end of the housing.

9. A magneto comprising a housing with a partition at one end, said partition having a central opening, a pole shoe assembly supported by said partition, a shaft, bearings for said shaft, means on the housing for supporting said bearings to hold the shaft in correct position, a web within the housing connected to the partition, a rotor mounted in the web, a pole shoe assembly having windings connected to and supported by the partition, gearing toenable the rotor to be driven from the shaft, and a distributor plate carrying fixed contacts to cooperate with the rotor.

10. A magneto comprising a framework having a partition partly closing one end and a web within the framework connected to the partition; stator parts comprising generator windings and a magnet supported on said partition, a bearing in said web, a rotor in the bearing, said rotor comprising a conducting arm and a contact brush, means in the rotor to connect said arm to the windings, a distributor plate at the opposite end of the housing carrying contacts to be engaged by the brush, a shaft for the magneto, gearing connecting the rotor and the shaft, a bearing for the shaft, means for supporting the bearing below the distributor; a second bearing, and means for supporting the second bearing from the stator of the magneto, and a cover for the stator parts of the magneto attached to said housing.

11. A magneto comprising a housing in the form of a plate having an overturned rim with a thickened portion enveloped by said rim, a stator including polepieces in the housing secured to said thickened portion, a shaft extending through said portion, a bearing for said shaft in said portion, an end plate directly supported solely by the stator in line with said portion and a second bearing for the shaft mounted in said end plate.

12. A magneto comprising a housing, a stator comprising polepieces within the housing and secured thereto, a shaft projecting from the housing, a bearing in the housing for the shaft, distributing mechanism in the housing, a gear on the shaft between the bearing and the stator to drive said mechanism, an end plate secured to the opposite side of the stator and directly supported solely thereby and a second bearing for the shaft in said end plate.

13. A magneto comprising a housing with a circular rim, said housing having an opening for a shaft, an annular projection concentric with said opening, stator members comprising pole pieces and generating windings engaging said projection on one side and mounted on the housing thereby and an end plate having a projection engaging the opposite side of said stator members and being secured thereto and supported thereon, a rotor to cooperate with the stator, a shaft for said rotor and bearings supported by the casing and the end plate for said shaft.

14. A magneto comprising a housing having a circular rim, and provided with an opening, an annular rib surrounding said opening, a stator comprising pole pieces and generating windings engaging said projection on one side and secured to the housing and supported by said projection, an' end plate having an annular projection to enable it to be mounted on the opposite side of the stator and be supported thereby, bearings carried by the housing and the end plate, a shaft in said bearings, a rotor in the shaft to c0- operate with the stator and a bent magnetconnected to the pole pieces of the stator, the plane of said magnet being at right angles to the common plane of the pole pieces.

In testimony whereof I afiix my signature.

J OI-IN F. MARTIN. 

